Circulatory responses to a CO₂ buffer following lethal injections of endotoxin

¹ Departments of Physiology and Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota

The circulatory actions of a CO₂ buffer (THAM) have been studied in the isolated perfused dog leg and kidney and in the intact dog. Techniques involving controlled arterial inflow were used in order that changes in vascular resistance could be calculated. Changes in organ weight were correlated with alterations in vascular resistance and hematocrit. Cardiac inflow was controlled and monitored in total body perfusion experiments in order that total peripheral resistance calculations and changes in venous return could be readily obtained. The infusion of THAM results in marked decreases in vascular resistance of leg, kidney and the totally perfused intact animal. Following the onset of THAM infusion there is a significant increase in venous return, brought about primarily by the reabsorption of tissue fluid. The vascular effect of THAM on the kidney may account for the profound diuretic action, although its use during prolonged hypotension appears to be detrimental. The findings of the present study indicate that the possible uses of THAM in hypertension and edema are worthy of investigation.